For reading out a capacitive MEMS (Microelectromechanical system) sensor, a readout circuit may be used which is based on biasing the sensor with a known voltage and sensing current or biasing a sensor capacitance at a known amount of charge and sensing voltage variations. However, this requires biasing references which may imply the use of charge pumps at the extra cost of area, current consumption and eventual need for high voltages devices, i.e. capacitors. Accordingly, MEMS circuit readout circuits which are more efficient, e.g. in terms of chip area and power consumption are desirable.